Turbine installation

ABSTRACT

The invention relates to a turbine installation ( 2 ), especially a gas turbine installation. In particular, the foot plates ( 32 ) of the guide blades ( 18 ) of adjacent turbine stages ( 28,30 ) are interconnected with a clip-type sealing element ( 42 A to  42 D) on their rear sides ( 48 ) facing away from the gas area ( 12 ). This provides a simple seal between adjacent foot plates ( 32 ) which is effective regardless of the thermal expansion of the foot plates ( 32 ). Said clip-type sealing element ( 42 A to  42 D) is also suitable for sealing the tiles ( 13 ) of a combustor ( 4 ) of the turbine installation ( 2 ) together.  
     Bei einer Turbinenanlage ( 2 ), insbesondere Gasturbinenanlage sind insbesondere die Fuβplatten ( 32 ) von Leitschaufeln ( 18 ) benachbarter Turbinenstufen ( 28,30 ) auf ihren vom Gasraum ( 12 ) abgewandten Rückseiten ( 48 ) über ein klammerartiges Dichtelement ( 42 A bis  42 D) miteinander verbunden. Dadurch ist eine einfache Abdichtung zwischen benachbarten Fuβplatten ( 32 ) erzielt, die unabhängig von der thermischen Ausdehnung der Fuβplatten ( 32 ) wirksam ist. Das klammerartige Dichtelement ( 42 A bis  42 D) ist ebenfalls geeignet, um Kacheln ( 13 ) einer Brenuklammer ( 4 ) der turbinenanlage ( 2 ) zueinander abzudichten.

[0001] The invention relates to a turbine plant, in particular a gasturbine plant.

[0002] By a gas turbine plant is meant hereafter a plant which comprisesa combustion chamber and a turbine located downstream of the combustionchamber and designated as a gas turbine. In the combustion chamber, afuel gas is burnt in a gas space, and the hot gas generated at the sametime is supplied to the turbine and flows through the latter. The flowpath of the hot gas through the turbine is likewise designated hereafteras the gas space. The turbine has stationary guide vanes, which extendradially from outside into the gas space, and moving blades which aremounted on a shaft designated as a rotor and which extend radiallyoutward from the rotor. As seen in the longitudinal direction of theturbine, the guide vanes and the moving blades engage one into the otherin a tooth-like manner. The turbine, as a rule, has a plurality ofturbine stages, a guide vane ring being arranged in each stage, that isto say a plurality of the guide vanes are arranged next to one anotherin the circumferential direction of the turbine. The individual guidevane rings are arranged successively in the axial direction. Both at thecombustion chamber and at the turbine, the gas space is conventionallylined with plate elements. At the combustion chamber, these are tiles,and at the turbine the plate elements are formed by what are known asfoot plates of the individual guide vanes.

[0003] The gas region of the combustion chamber and of the turbine is tobe as leaktight as possible. The aim is therefore to have insignificantleakage losses between the individual plate elements. In particular,leakage losses between two turbine stages are to be prevented. As aresult of the high temperature spans in the gas space, there is theproblem that a seal has to absorb and bridge expansions of theindividual plate elements, without the seal being appreciably impaired.This problem is aggravated by the fact that neither the tiles nor thefoot plates of the guide vanes are fastened at their edge regions toadjacent plate elements, so that the plate edges are to a greater orlesser extent free and undergo bending as a result of thermal expansion.The tiles, for example, are, as a rule, fastened in their center andbend approximately spherically under thermal load. A seal must thereforeallow both axial and radial movability, also because the combustionchamber and the turbine are designed conically in the axial direction.

[0004] In a conventional seal, the foot plates are provided in theregion of the turbine with a groove on their end face, a sealing sheetbeing inserted into the grooves of two foot plates of guide vanes ofadjacent turbine stages. Where the end-face grooves are concerned, theaxial and radial movability of the foot plates is achieved in that thegrooves have oblique side walls. However, grooves of this kind arehighly complicated in production terms. Moreover, a seal of this kind isrelatively leaky, since a varyingly rapid thermal expansion behavior ofthe foot plates and of what is known as the turbine guide vane carrierto which they are fastened must be taken into account. To be precise,when the turbine is started up, the foot plates expand more rapidly, sothat a leakage gap between the foot plates is initially closed. Theleakage gap opens again when the turbine guide vane carrier has expandedaccording to the temperature.

[0005] As regards the tiles in the combustion chamber, there isadditionally the problem that, because they bend spherically, such asealing sheet is sometimes subjected to shearing load until it fails.

[0006] The object on which the invention is based is to make it possibleto have a seal which overcomes the disadvantages described.

[0007] The object is achieved, according to the invention, by means of aturbine plant, in particular a gas turbine plant, with a gas space whichis outwardly delimited via plate elements contiguous to one another, asealing element being assigned in each case to plate elements adjacentto one another and connecting these to one another in a staple-likemanner on their rear sides facing away from the gas space.

[0008] The essential advantage is to be seen here in the staple-likeconfiguration of the sealing element. The sealing element thus spans thetwo plate elements. Under thermal expansions, the sealing elementfollows the plate elements, without opening up a gap. The seal producedby the sealing element is therefore largely unaffected by thermalexpansions.

[0009] In order to ensure as good a seal as possible, even underall-round thermal expansions, the sealing element preferably allows amovability of the plate elements both in the axial and in the radialdirection. The sealing element is therefore designed, in particular, tobe elastic both in the axial and in the radial direction. By axialdirection is meant here an expansion in the longitudinal direction ofthe turbine plant and by radial direction an expansion perpendicular tothe longitudinal axis.

[0010] Preferably, the sealing element has two limbs which engage ineach case into a groove of plate elements adjacent to one another. Thismakes it possible to have a fastening of the sealing elements which issimple to implement in production terms.

[0011] Preferably, the groove extends from the rear side of therespective plate element into the latter, essentially radially. Thelimbs therefore project radially outward from the grooves. Thisconfiguration of the groove allows simple production and, in particular,high accuracy, for example by grinding or erosion. The advantage of thearrangement on the rear side is to be seen in that the groove does nothave to be of a special shape with regard to the problem of thermalexpansions. The groove and sealing element can therefore be adapted veryaccurately to one another, so that very small leakage gaps are achieved.

[0012] In order to make it possible to have a simple procedure formounting the plate elements in the turbine plant, the sealing element ispreferably of multipart construction.

[0013] In this case, preferably, the limbs of the multipart sealingelement overlap one another over a common circumferential length. Thiscircumferential length is in this case dimensioned sufficiently largeessentially to avoid leakages.

[0014] In a preferred embodiment, the sealing element is of U-shapeddesign, this being simple to implement both in production terms and inassembly terms.

[0015] In order to achieve a high expandability of the sealing element,the latter has a wavy structure in the manner of a concertina in orderto absorb expansions.

[0016] Expediently, the sealing element has this wavy structure in aplurality of directions, so that it can absorb expansions in differentdirections. In particular, the sealing element has a configuration inthe form of a double S.

[0017] In a preferred embodiment, the sealing element is arrangedbetween adjacent tiles of a combustion chamber. Reliable sealing betweenthe tiles is consequently achieved, even when these bend spherically asa result of thermal load.

[0018] According to a particularly preferred embodiment, the sealingelement is arranged between the foot plates of adjacent guide vanes of aturbine, specifically, in particular, between the foot plates of guidevanes of adjacent turbine stages.

[0019] The individual foot plates are accordingly connected to oneanother in the axial or the longitudinal direction of the turbine viastaple-like sealing elements.

[0020] In order to achieve simple mounting of the plate elements, inparticular of the foot plates, and at the same time good sealing of theplate elements both in the circumferential direction and in the axialdirection between adjacent turbine stages, preferably, the staple-likesealing element described is provided for sealing in the axial directionand a further sealing element is provided for sealing in thecircumferential direction. Depending on the direction, therefore, and inparticular for assembly reasons, differently designed sealing elementsare used.

[0021] The further sealing element in this case preferably has areception region, into which the plate elements extend. In particular,the sealing element is designed with an H-shaped cross section. Thefundamental idea of this configuration is to be seen in the reversal ofa conventional sealing principle, in which a sealing sheet is introducedinto corresponding end-face grooves of the foot plates. To be precise,this, as a rule, necessitates a reinforcement of the edge of the footplates in the groove region. This presents problems with regard to aneffective cooling of the foot plates, since, on account of the differentmaterial thicknesses, a uniform cooling can be implemented only withdifficulty and thermal stresses may occur. In this case, in a reversalof this sealing principle, the sealing sheet is not inserted into thefoot plates but, instead, the foot plates are introduced into thesealing element. This avoids the need for a reinforcement of the edgeregion of the foot plate. Coolability is thus simplified and the footplate is cooled homogeneously in all regions, so that no thermalstresses occur.

[0022] Exemplary embodiments of the invention are explained in moredetail hereafter with reference to the drawing, in which, in each casein a roughly simplified illustration,

[0023]FIG. 1 shows a turbine plant with combustion chamber and turbine,

[0024]FIGS. 2 and 3 show different conventional seal variants,

[0025]FIG. 4 shows the seal variant according to the invention,

[0026] FIGS. 5-7 show different variants of a seal element, and

[0027]FIG. 8 shows a seal provided, in particular, for plate elementsarranged next to one another in the circumferential direction.

[0028] According to FIG. 1, a turbine plant 2, in particular a gasturbine plant of a turbo set for a power station for energy generation,comprises a combustion chamber 4 and a turbine 6 which is arrangeddownstream of the combustion chamber 4 in the longitudinal or axialdirection 8 of the turbine plant 2. Both the combustion chamber 4 andthe turbine 6 are illustrated, cut away, in a part region. It isconsequently possible to look into the gas space 10 of the combustionchamber 4 and into the gas space 12 of the turbine 6.

[0029] During operation, the combustion chamber 4 is supplied via a gassupply 14 with a fuel gas BG which is burnt in the gas space 10 of thecombustion chamber 4 and forms a hot gas HG. The gas space 10 is linedwith a multiplicity of tiles 13 designed as plate elements. The hot gasHG flows through the turbine 6 and leaves the latter as cold gas KG viaa gas discharge line 16. The hot gas HG is guided in the turbine 6 viaguide vanes 18 and moving blades 20. In this case, a shaft 22, on whichthe moving blades 20 are arranged, is driven. The shaft 22 is connectedto a generator 24.

[0030] The moving blades 20 extend radially outward from the shaft 22.The guide vanes 18 have a foot plate 32 and a vane leaf 21 fastened tothe latter. The guide vanes 18 are in each case fastened outwardly tothe turbine 6 on what is known as a guide vane carrier 26 via their footplates 32 and extend radially into the gas space 12. As seen in thelongitudinal direction 8, the guide vanes 18 and the moving blades 20engage one into the other in a tooth-like manner. A plurality of movingblades 20 and of guide vanes 18 are in this case combined to form aring, each guide vane ring representing a turbine stage. In theexemplary embodiment of FIG. 1, the second turbine stage 28 and thethird turbine stage 30 are illustrated by way of example.

[0031] The foot plates 32 of the individual guide vanes 18, like thetiles 13, are designed as plate elements which are contiguous to oneanother both in the axial direction 8 and in the circumferentialdirection 33 of the turbine 6 and which delimit the gas space 12. Thelocation marked by a circle in FIG. 1 is illustrated, enlarged, in FIGS.2 to 4. The seal, described with regard to these figures, between twofoot plates 32 which, in particular, are arranged next to one another inthe longitudinal direction 8 can also be transferred accordingly to forma seal for the tiles 13 of the combustion chamber 4.

[0032] According to FIG. 2, in a conventional variant illustrated here,sealing is carried out, without a special sealing element, solely byvirtue of an overlap of foot plates 32 adjacent to one another. The twofoot plates 32 have a step-shaped design in the overlap region. Underthermal stress and the associated expansion, the two foot plates 32 aredisplaced relative to one another in a movement superposed in thelongitudinal direction 8 and in the radial direction 36. The leakage gap38 formed between the two foot plates 32 varies as a result. The sealingaction thus depends decisively on the expansion behavior of the footplates 32.

[0033] The foot plates 32 according to FIGS. 2 to 4, each have, on theirrear side 39 facing away from the gas space 12, a hooking element 40 viawhich the foot plates 32 are held on the guide vane carrier 26 (cf. FIG.1). Each foot plate 32 in this case typically has two hooking elements40 which are configured differently and allow movability both in theaxial direction 8 and in the radial direction 36.

[0034] According to FIG. 3, a further conventional sealing arrangementhas a sealing sheet 41 which is inserted into grooves 44 in the adjacentfoot plates 32. The grooves 44 are in this case worked into the endfaces 46 of the foot plates 32. They have an opening angle α ofapproximately 15°, in order to allow a movability of the foot plates 32in the radial direction 36. In this embodiment, too, there is formedbetween the sealing sheet 41 and the foot plates 32 a leakage gap 38which varies with expansion as a result of the thermal load. Thisvariation is caused, inter alia, by the fact that the foot plates 32expand more rapidly than the guide vane carrier 36 to which they arefastened.

[0035] In particular, the problems of the temperature dependence of theleakage gap 38 do not arise in the novel configuration according to FIG.4. According to this, grooves 44, which extend essentially radially intothe foot plates 32, are worked into the rear side 39 of the two footplates 32 in the region in which the latter are contiguous to oneanother. It must be stressed that the grooves 44 according to FIG. 4have parallel side walls 50, in contrast to those of FIG. 3. This allowsa particularly simple production of the grooves 44.

[0036] A U-shaped sealing element 42A is introduced with its two limbs52 into the grooves 44 and, in particular, is fastened. Fastening iscarried out, for example, by means of a clamping action or else bywelding. The sealing element 42A is produced, in particular, as asheet-metal element. Its limbs 52 extend outward, essentially in theradial direction, so that the arc 54 connecting the two limbs 52 is at adistance from the rear side 39. This elongate design makes it possiblefor the sealing element 42A to have an elastic behavior, that is to sayit follows the thermal expansions of the foot plates 32. The thermalmovability of the foot plates 32 is thus ensured by the bendable orexpandable sealing element 42A. Movability is therefore independent ofthe special configuration of the grooves 44, so that these can beadapted with a highly accurate fit to the limbs 52. Between the limbs 52and the grooves 44, therefore, no or only a very small leakage gap 38 isformed, which is independent of the thermal stress on the foot plates32.

[0037] Alternative embodiments of the sealing element 42A areillustrated by way of example in FIGS. 5 to 7. According to FIG. 5, asealing element 42B is formed from two separate limbs 52 which each havean arc 54 and overlap one another over a circumferential length L. Themultipart design of the sealing element B simplifies mounting, since,for example, individual limbs 52 can simply be fastened into thecorresponding grooves 44 of the respective foot plates 32, even beforethe mounting of the guide vanes 18, and said foot plates cansubsequently be attached to the guide vane carrier 26. The commoncircumferential length L selected is in this case as large as possible,in order to keep the leakage gap 38 formed between them small for allthermal and operating states.

[0038] In an alternative multipart design of a sealing element 42Caccording to FIG. 6, only one limb 52A is provided with an arc 54,whereas the second limb 52B is a straight sheet-metal piece. In themultipart sealing elements 42B, 42C it is advantageous if the individuallimbs 52 are pressed against one another in the mounted state and, forexample, have some spring tension.

[0039] According to FIG. 7, a sealing element 42D is provided with awavy structure 58 which replaces the simply configured arc 54 accordingto FIGS. 4 to 6. This wavy structure 58 extends preferably in aplurality of directions, in particular in the two directions parallel tothe foot plates 32. In addition, the limbs 52, too, may be wavy. Thesealing element 42D is thus designed in the manner of a concertina andmakes it possible to absorb even high thermal expansions in a pluralityof directions, without the leakage gap 38 being enlarged.

[0040] The sealing elements 42A to 42D preferably connect the footplates 32 of guide vanes 18 of adjacent turbine stages 28, 30 forassembly reasons. In order to achieve a good and simply mountable sealeven in the circumferential direction 33, a further sealing element 60is provided for guide vanes 18 of a guide vane ring which are adjacentto one another in the circumferential direction 33.

[0041] According to FIG. 8, the further sealing element 60 is preferablydesigned with an H-shaped cross section and has two longitudinal limbs62 which are connected to one another via a transverse limb 64. Betweenthe two longitudinal limbs 62 are formed two reception regions 65 whichare separated from the transverse limb 64 and into which the foot plates32 extend. The side edges 66 of the foot plates 32 are bent away outwardfrom the gas space 12 approximately perpendicularly and fit snuglyagainst the transverse limb 64.

[0042] This configuration with the reception regions 65 for the footplates 32 advantageously makes it possible to have a material thicknesswhich is homogeneous over the entire foot plate 32, so that uniformcooling of the foot plate 32 is ensured and thermal stresses in the footplate 32 do not occur.

[0043] To cool the foot plates 32, in particular, a closed coolingsystem 68, a detail of which is illustrated in FIG. 8, is provided, withsteam as the coolant. This closed cooling system 68 has an inflow duct70 and a return-flow duct 72. The inflow duct 70 is formed between anouter guide sheet 74 and a baffle sheet 76, which is arranged betweenthe guide sheet 74 and the foot plate 32. The baffle sheet 76 has floworifices 78 which are designed in the manner of nozzles, so that thecoolant supplied via the inflow duct 70 flows over into the return-flowduct 72 along the arrows illustrated. By virtue of the nozzle-likeoperation of the flow orifices 78, the coolant is guided at highvelocity against the rear side 80 of the foot plate 32, so thateffective heat transmission between the coolant and the foot plate 21 isimplemented.

[0044] The baffle sheet 76 is supported against the foot plate 32 andkept at a distance from the latter via supporting elements 82, forexample in the form of weld spots or welded webs. The baffle sheet 70 isdirectly fastened, in particular welded, to the side edge 66 of the footplate 32 and the guide sheet 68 is fastened to the baffle sheet 70.

[0045] A flow path 84 in the form of a leakage gap is formed between thefurther sealing element 60 and at least one of the foot plates 32, sothat, for example, air from the outside space 86 facing away from thegas space 12 can flow via the flow path 84 into the gas space 12 andconsequently cools the seal region, that is to say the sealing element60 and the side edges 66.

1. A turbine plant (2), in particular a gas turbine plant, with a gasspace (10, 12) which is outwardly delimited via plate elements (13, 32)contiguous to one another, a sealing element (42A-D) which has two limbs(52) being assigned in each case to plate elements (13, 32) adjacent toone another and connecting these to one another in a staple-like manneron their rear sides (48) facing away from the gas space (10, 12), inthat the sealing element (42A-D) engages in each case with a limb (52)into a groove (44) which is arranged in each case in plate elements (13,32) adjacent to one another.
 2. The turbine plant (2) as claimed inclaim 1, in which the sealing element (42A-D) allows a movability of theplate elements (13, 32) both in the axial direction (8) and in theradial direction (36).
 3. The turbine plant (2) as claimed in one of thepreceding claims, in which the groove (44) extends from the rear side(48) of the respective plate element (13, 32) into the latter,essentially radially.
 4. The turbine plant (2) as claimed in one of thepreceding claims, in which the sealing element (42B, C) is of multipartconstruction.
 5. The turbine plant (2) as claimed in claim 4, in whichthe two limbs (52) of the multipart sealing element (42B, C) overlap oneanother over a common circumferential length (L).
 6. The turbine plant(2) as claimed in one of the claims, in which the sealing element(42A-C) is of U-shaped design.
 7. The turbine plant (2) as claimed inone of the preceding claims, in which the sealing element (42D) has awavy structure in the manner of a concertina in order to absorbexpansions.
 8. The turbine plant (2) as claimed in claim 7, in which thesealing element (42D) has the wavy structure (58) in a plurality ofdirections.
 9. The turbine plant (2) as claimed in one of the precedingclaims, in which the sealing element (42A-D) is arranged betweenadjacent tiles (13) of a combustion chamber (4).
 10. The turbine plant(2) as claimed in one of the preceding claims, in which the sealingelement (42A-D) is arranged between the foot plates (32) of adjacentguide vanes (18) of a turbine (6).
 11. The turbine plant (2) as claimedin one of the preceding claims, which extends in the axial direction (8)and in which the sealing element (42A-D) is arranged between axiallyadjacent plate elements (13, 32), in particular between the foot plates(32) of guide vanes (18) of turbine stages (28, 30) adjacent to oneanother.
 12. The turbine plant (2) as claimed in claim 11, in which afurther sealing element (60) with a reception region (65), into whichthe plate elements (13, 32) extend, is provided between plate elements(13, 32) adjacent to one another in the circumferential direction (33),in particular between the foot plates (32) of guide vanes (18).